As advertisers and media agencies, we sign the Insertion Orders (IOs) and then assume that the publishers are placing our ads at the correct placement and also targeting the right audience.
What goes on in reality? Obviously, a certain percentage of these ads end up in areas of the Internet where it doesn't make any sense (Adult content, areas not relevant to the brand etc) or might get served below the fold or even get served to out of the country audience.
What if you are an e-tailer in UK and your deal of the week ads are being served to people in India or USA or Brazil. It's a waste of media i.e. waste of money. There will hardly be anyone in India, USA or Brazil looking to buy from your online store in UK.
Similarly, if you are a technology company targeting your ads towards gamers but your ads appear within parenting section. The likelihood of conversion in parenting section are really slim.
There are now audit services available that can audit your online media buys and tell you exactly where your ads are being served. Are your ads being served to an international audience, are your ads being served in the areas that are not relevant.
DoubleVerify is a service which can provide you this information. They claim to have relationships with majority of the publishers and seem to be well known. It seems to be pretty simple to use them if you use third party ad-serving like DoubleClick, Atlas.
DoubleVerify provides you screenshots of your ads in inappropriate content, international traffic, below the fold ads, multiple impressions on the same page. All this information can be used by advertisers or media agencies to renegotiate the media buy with the publishers. Net net bringing additional savings to your client or your own business.